#start pattern
my name is $name
blahhhhhhh
my id is $id
blahhhh
#Endpattern

#newpattern
my name is $name
blash
my id is $id
#endofpattern

#startpattern
my name is $name
blaghhh
my id is $id
#endpattern

#start pattern
my name is fred
blahhhhhhh
my id is 42
blahhhh
#Endpattern

#1064933.txt

##</code><code>##

#!/usr/bin/perl
use 5.016;
use warnings;

# 1064933

my $name="guest";
my $id = 1;

$/ = "\n\n";

open(SOURCE, "<1064933.txt") or die "Can't open 1064933.txt, $!";
open(SINK, ">1064933OUT.txt") or die "Can't open 1064933OUT.txt, $!";
while (<SOURCE>) {
    if ( /start pattern/ .. /Endpattern/) {
        s/\$name/$name/;
        s/\$id/$id/;
        print SINK $_;
        next;
    }
}

##</code><code>##

D:\_Perl_\PMonks>cat 1064933OUT.txt
#start pattern
my name is guest
blahhhhhhh
my id is 1
blahhhh
#Endpattern

#start pattern
my name is fred
blahhhhhhh
my id is 42
blahhhh
#Endpattern